padding and centering TextSpanner text

[Kieren MacMillan]

Hello all,

In the attached snippet, I’d like to have:
    (a) a little padding between the TextSpanner line and the bits of text on 
both sides (without having to cook it into the text itself); and
    (b) the text bits centered over their respective noteheads.

I can’t seem to find the correct parameters: all attempts with attach-dir, 
etc., have failed to provide consistent results regardless of the text(s) 
chosen.

Any help would be appreciated.

Thanks!
Kieren.

%%%%  SNIPPET BEGINS
\version "2.19"

\layout {
  indent = 0
  line-width = 6\in
  ragged-right = ##f
}

spannerstuff = {
  \omit Score.TimeSignature
  \omit Score.BarNumber
  \override TextSpanner.dash-fraction = #1
  \override TextSpanner.dash-period = #1
  \override TextSpanner.bound-details.left.stencil-align-dir-y = #0
  \override TextSpanner.bound-details.right.stencil-align-dir-y = #0

  \once \override TextSpanner.bound-details.left.text = "22222"
  \once \override TextSpanner.bound-details.right.text = "33"
  c''2\startTextSpan c''\stopTextSpan
  \break
  \once \override TextSpanner.bound-details.left.text = "33"
  \once \override TextSpanner.bound-details.right.text = "22222"
  c''2\startTextSpan c''\stopTextSpan
}

\score {
  \spannerstuff
}
%%%%  SNIPPET ENDS

________________________________

Kieren MacMillan, composer
‣ website: www.kierenmacmillan.info
‣ email: address@hidden